steppers worked fine on one machine , shakes on another

Hi !

I recently salvaged a prusa i3 so I could use some of its parts in a "drawing robot" , but the steppers shake intensely and do move (the coils are connected properly) but the shaking is
so extreme that the entire thing just moves when I put it on the ground , and this sort of shaking was nonexistent when the motors were on the prusa .
I have tried 1/16 and 1/32 microstepping (because switching to 1/32 saved me from this shaking once in the past) but nothing changed. I also tried fine tuning the potentiometer on the
driver but it shakes no matter how much current it gets.
I also have another issue regarding grbl itself but I have no idea where to ask , because I believe this forum is about bigger machines than what I am working on ?

thanks in advance !

You may be trying to spin it too fast. Try to reduce the 'feedrate' and acceleration and see if that helps, steppers can only handle so much torque (in the form of acceleration and speed) before they go crazy. What type of drivers are you using?

the prusa i3 is a light weight machine so the stepper drivers will be low power and motors have a low torque

what is the new machine like ?

if its larger and heavier , the motor could be stalling

photos are helpful

the more detail you can give the easier it will be for others to help


John

PS

I expect your stepper drivers are something like the Reprap Stepper Driver A4988 Stepper MotorDriver Module

Attachment 430348

Hi ! thanks !
Yes I am using polulu drivers (DRV8825) , I will try changing the acceleration.
the torque requirements for this application is much less than the 3d printer itself , so I assume it is a speed/acceleration issue , but grbl is more confusing than 3dprinter firmwares since theres less documentation.
thanks !